Suspecting his wife's fidelity, a 28-year-old man first killed his five-year-old son by pushing his face into a bucket full of water and then hanged himself at home in Bangalore on Wednesday, police said.

The wife who had gone away to her relative's place, fed up with the daily quarrels, consumed poison there and subsequently died in hospital, police said.

Santhosh Kumar, who was working in an automobile showroom for the past three years, left a suicide note which said that his wife's illicit relationship with another man had pained him to a great extent resulting in him taking the extreme step, police said.